Certain gas sensors leverage physical or chemical changes in a chemical sensing material, e.g., a chemiresistor material, while in the presence of a gas to determine the concentration of that gas in the surrounding environment. However, chemiresistor-based gas sensors cannot sense inert gases, such as carbon dioxide or nitrogen, due to reaction limitations of metal-oxide-semiconductor (MOS) structures. Accordingly, it would be desirable to implement gas sensor devices that can detect a wider variety of gases.